There's nothing wrong with that. At that time, there were only a few machines (presumably only satoshi's)* running to mine Bitcoins.

The network does try to keep the blocks at an interval of 10 minutes. At that time, the difficulty was set at 1 and it is impossible to go lower than that, as per the algorithm that calculates the difficulty.

**Lol actually nevermind, I thought Hal Finney had his transaction a lot later than that. I would still say that only a few people mined Bitcoins at that time.